Hanna Instruments HI 2216 - Manual (Page 9)

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Calibrate the instrument frequently, especially if high accuracy is
required.
The instrument should be recalibrated:
• Whenever the pH electrode is replaced.
• At least once a week.
• After testing aggressive chemicals.
• If “
CAL” “INTV” tags are blinking during measurement.
Every time you calibrate the instrument use fresh buffers and perform an
electrode Cleaning Procedure (see page 42).
PREPARATION
Pour small quantities of the buffer solutions into clean beakers. If
possible, use plastic or glass beakers to minimize any EMC interferences.
For accurate calibration and to minimize cross-contamination, use two
beakers for each buffer solution. One for rinsing the electrode and one for
calibration.
If you are measuring in the acidic range, use pH 7.01 or 6.86 as first
buffer and pH 4.01 as second buffer. If you are measuring in the alkaline
range, use pH 7.01 or 6.86 as first buffer and pH 10.01 or 9.18 as
second buffer.
PROCEDURE
Calibration can be performed up to five-points.
For accurate measurements a three
-point calibration is recommended.
The calibration buffer can be selected from the calibration buffer list that
includes the custom buffers and the memorized standard buffers:
•
pH 1.68, 4.01, 6.86, 7.01, 9.18, 10.01 and 12.45.
TEMPERATURE MEASUREMENTS
Connect the HI 7662 temperature probe to the
appropriate socket and turn the instrument on.
Submerse the temperature probe into the sample
and allow the reading on the secondary LCD to stabi-
lize.